Study on dynamic characteristics of sea-bed clay under pure circular stress path under wave load

At present, the study of the effect of wave load on saturated silty clay is still mainly based on the laboratory dynamic triaxial experiment, which cannot truly reflect the continuous rotation of the principal stress axis caused by wave load. In this study, the dynamic hollow cylindrical apparatus (DHCA) is used to carry out cyclic shear tests and post-cyclic tests on Taizhou silty clay with different cyclic stress ratio and cycle numbers under wave loading. The cyclic characteristics, such as the development of pore water pressure, stress-strain relationship, backbone curve and stiffness were studied and analyzed, and the relationship function between the backbone curve and cycle numbers is established. Besides, under the same CSR condition, the shear strength after the wave loading is positively correlated with the cycle numbers. And the shear modulus E₅₀ increases with the increasing cycles, indicating the possible stiffness hardening, instead of the stiffness softening after cyclic loading in most previous triaxial tests. This study provides new experimental evidence and theoretical references for evaluating the engineering properties of saturated silty clay under wave loading.